ISO 9618 Aerospace - Nuts, hexagonal, slotted (castellated), reduced height, normal across flats, with MJ threads, classifications: 450 MPa (at ambient temperature)/120 °C, 450 MPa (at ambient temperature)/235 °C, 600 MPa (at ambient temperature)/ 425 °C, 900 MPa (at ambient temperature)/235 °C, 900 MPa (at ambient temperature)/315 °C, 900 MPa (at ambient temperature)/ 650 °C, 1 100 MPa (at ambient temperature)/235 °C, 1 100 MPa (at ambient temperature)/ 730 °C and 1 250 MPa (at ambient temperature)/600 °C - Dimensions - Second Edition